There are many situations in which it is important to perform inspections at locations that are difficult or impossible to access directly by a person. For example, such locations may be deep within an apparatus or structure, possibly requiring navigation of a complex or tortuous path, and/or may be within a sealed, enclosed, or otherwise inaccessible enclosure, or may simply be remote from any location directly accessible by a person. Such inspections are not necessarily limited to visual inspections, but and include inspection using any one or more of a wide variety of different types of inspection devices or sensors, typically (but not necessarily) in combination with visual inspection.
For example, preventive maintenance inspections of a structure or apparatus are commonly conducted using a schedule-based inspection regime that is imposed by its manufacturer and/or by a regulatory body. Often this involves disassembling the structure/apparatus, finding nothing, and then reassembling. Such a necessary but fruitless exercise comes at the expense of wasted downtime, wasted inspector time, added cost, and sometimes the accidental production of maintenance-induced damage or faults. Conversely, sometimes it happens that significant and unforseen damage is unexpectedly found during an inspection, leading to extended platform downtime (often exacerbated by lead times for spare parts), higher than expected labour time and costs for repair, and a significant impact on total maintenance resources and operation.
In this regard, the burden of corrosion is becoming increasingly significant across a number of industries due to factors such as increased pressure to extend service life, operations in more severe environments, reduced effectiveness of environmentally-friendly corrosion inhibitors, increased OH&S requirements for access into dangerous spaces, overly rigorous mandated inspection regimes causing maintenance-induced damage, and other causes.
For example, defence forces are becoming increasingly concerned at the increasing cost and platform downtime due to corrosion, and it is not unusual to lose more than 10% of an annual fleet availability due to corrosion. One recent study concluded that aircraft corrosion cost the Australian Defence Force $238 M in 2013. Moreover, maintenance regimes also exist where two-thirds of scheduled inspections are for corrosion, and more damage is done by the resulting disassembly and reassembly of the structure than by actual material oxidation.
However, maintenance inspection is only one reason to inspect difficult to access locations.
It is desired, therefore, to address or alleviate one or more difficulties of the prior art, or to at least provide a useful alternative.